These envelopes are excellent. There were a few times I needed to get the contents out to change something after already having sealed the envelope and to my surprise the envelope could still be used and resealed without a problem (with maybe a tiny wrinkle or two).
These are great envelopes in terms of quality as to how they protect visibility of the contents. Pulling the strip to expose the adhesive is easy and the envelopes seal well. I plan to continue using these at my office.